/u/Astrogator previously answered a similar question on Hitler's health and drug use:

https://np.reddit.com/r/AskHistorians/comments/3qat0p/how_fit_was_hitler/cwduf3x/

In summary, Hitler was not in an abnormal state of mind caused by drug abuse when he made the most important decisions of his political career or the war.

/u/commiespaceinvader has previously written about Hitler's drug use in response to a (then) newly translated book by Norman Ohler. Also remember that focusing on Hitler as an historical agent isn't always helpful.